NASA has released stunning new infrared images of interstellar comet 3I/ATLAS, which unexpectedly flared while it was exiting the solar system. This surge in activity has captured the interest of scientists and sparked renewed speculation about the comet’s origins. Observations from NASA’s SPHEREx telescope revealed that in December 2025, the comet displayed a significant increase in activity, contrary to expectations that it would gradually fade after its closest approach to the Sun.
The comet, which was discovered in July 2025, is only the third confirmed interstellar object to pass through the solar system. Unlike typical comets that become most active near their perihelion, or closest point to the Sun, 3I/ATLAS experienced its most intense activity well after this point. The comet released a remarkable amount of gas, dust, and complex molecules, creating a glowing coma rich in water vapor, carbon dioxide, and organic compounds.
Unexpected Brightness Captivates Scientists
“Rather than quietly dimming as it moved away, the comet became significantly brighter,” said Carey Lisse, lead author of the study, in a statement from NASA. The findings indicate that even water ice was rapidly converting to gas at great distances from the Sun.
The comet’s distinctive pear-shaped dust tail formed as rocky material was ejected into space during this outburst. Researchers suggest that sunlight may have taken time to penetrate a hardened outer crust of the comet, eventually reaching ice that had remained frozen for billions of years. Once this ancient material was warmed, it escaped into space, leading to the delayed flare observed by SPHEREx.
Insights into Interstellar Objects
SPHEREx is uniquely equipped to analyze such phenomena. Operating in infrared wavelengths, the telescope can identify not only dust but also various molecules emanating from the comet, including methane, methanol, and cyanide. These carbon-rich compounds are considered essential in the early stages of planet formation.
The chemical composition of 3I/ATLAS provides a rare opportunity to compare local comets with icy bodies formed around other stars. Preliminary results suggest the presence of many familiar ingredients, supporting the notion that the basic building blocks of planets may be widespread throughout the Milky Way.
Furthermore, scientists believe the comet’s long exposure to cosmic radiation during its interstellar journey has played a significant role in its behavior. Over extensive timescales, this radiation likely altered the comet’s surface, sealing off more pristine ice beneath. When solar energy finally reached these untouched layers, it triggered the sudden release of material.
The findings regarding comet 3I/ATLAS have been published in the February 2026 issue of Research Notes of the AAS. As the comet continues into deep space, now fading from view, its unexpected farewell offers valuable insights into the nature of interstellar objects and highlights the ongoing fascination they hold for both scientists and the public.
While some social media users have drawn parallels between the comet’s flare-up and a spacecraft “powering up,” scientists emphasize that there is no evidence to support theories of artificial origins. Instead, the behaviors exhibited by 3I/ATLAS reinforce the understanding of natural cosmic phenomena, reminding us of the wonders and mysteries that the universe holds.
